Toroidal CVT Retainer Oil Port Layout for Roller Lubrication
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Solution Overview
Problem
The existing pressing devices for toroidal continuously variable transmissions, such as those disclosed in JP 2006-002882(A), fail to sufficiently supply lubrication oil to rollers due to neglecting the Coriolis force effect, leading to potential fretting wear on the rolling surfaces and cam surfaces.
Innovation Solution
A pressing device with a retainer having oil passages and discharge ports that utilize the Coriolis force to efficiently distribute lubrication oil across the rollers, ensuring adequate lubrication, particularly for rollers positioned radially outward, by orienting discharge ports to open on the retainer's inside surface ahead of the pocket's center axis, allowing oil to move circumferentially and reach all rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubrication oil is supplied through conventional oil holes perpendicular to the retainer surface, then the structure is simple, but lubrication oil cannot be sufficiently supplied to rollers due to Coriolis force effects
Solution Approach 1:
The patent changes the orientation parameter of the discharge port from perpendicular to inclined relative to the retainer surface. This parameter change allows the lubrication oil to counteract the Coriolis force and reach the rollers effectively, improving lubrication sufficiency without significantly increasing structural complexity
Solution Approach 2:
The patent introduces a circumferential dimension to the oil supply by inclining the discharge port. Instead of oil flowing only radially outward, the inclined port creates a circumferential component in the oil flow direction, enabling the oil to reach rollers that would otherwise be inaccessible due to Coriolis force
2Reliability
If rollers are arranged in radial rows inside pockets, then space utilization is efficient, but rollers on the outside in radial direction are difficult to lubricate
Solution Approach 1:
The patent creates an asymmetric oil supply configuration by inclining the discharge port relative to the radial direction. This asymmetric orientation directs oil flow preferentially toward the outer rollers in the radial arrangement, compensating for the lubrication difficulty these rollers experience due to Coriolis force
3Reliability
If discharge ports open at the center axis of pockets, then the structure is symmetric and simple, but lubrication oil does not reach rollers effectively under Coriolis force
Solution Approach 1:
The patent changes the positional parameter of the discharge port from the center axis location to an inclined position relative to the center axis. This parameter change enables the oil flow to counteract Coriolis force and reach rollers effectively, improving lubrication effectiveness with a relatively simple positional adjustment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively suppresses fretting wear by ensuring sufficient lubrication across all rollers, improving the lubricated state between the rollers and cam surfaces, thereby enhancing the operational reliability of the toroidal continuously variable transmission.
Implementation Method 1
the effect of the Coriolis force acting on the lubrication oil that is discharged from the oil holes is not taken into consideration
Data Source
AI summary
Provided is a pressing device for a toroidal continuously variable transmission that is capable of sufficiently supplying lubrication oil to all rollers inside a pocket, and is capable of suppressing the occurrence of fretting wear on the rolling surfaces of the rollers, a first cam surface and a second cam surface. An oil passage 28 is provided for supplying lubrication oil to the inside of each pocket 25 in the inside portion in the radial direction of a retainer 14 that holds a plurality of more than one roller 13 arranged in a row in the radial direction. The center axis O29 of a discharge port 29 that is provided on an end portion on the downstream side of the oil passage 28 and that opens to the inside surface in the radial direction of the pocket 25 is inclined toward the front side in the rotational direction of the retainer 14 with respect to the center axis of the pocket 25.